Embodiments of the present invention relate to a semiconductor integrated circuit.
A semiconductor integrated circuit is supplied with a first power supply voltage VDD, a second power supply voltage VDDQ, a first ground voltage VSS, and a second ground voltage VSSQ through separate pins in order to ensure operational stability and provide various functions. The first power supply voltage VDD and the first ground voltage VSS are supplied to an internal control circuit of the semiconductor integrated circuit, and the power supply voltage VDDQ and the second ground voltage VSSQ are supplied for data transmission of the semiconductor integrated circuit.
The first ground voltage VSS and the second ground voltage VSSQ applied through the separate pins are transferred through voltage lines. Here, the voltage lines contain inductance components. Since inductance components generate a counter electromotive force having an opposite polarity to an external voltage, the voltage lines containing the inductance components mutually share high frequency power noises. As the inductance components of the voltage lines increase, the mutual sharing of the high frequency power noises between the voltage lines increases. Therefore, much research is being conducted to develop technologies which can substantially reduce the mutual sharing of power noises by shorting the voltage lines through which the first ground voltage VSS and the second ground voltage VSSQ are transferred in a high frequency range.
One of examples which short the voltage lines in the high frequency range is to couple the voltage lines, through which the first ground voltage VSS and the second ground voltage VSSQ are transferred, by metal lines. In the high frequency range, the metal lines substantially reduce inductance components of voltage lines through which the first ground voltage VSS and the second ground voltage VSSQ are transferred, thereby reducing the mutual sharing of power noises. However, if the power lines are connected by the metal lines, the short-circuited state of the voltage lines is maintained in all the frequency ranges, the voltage lines through which the first ground voltage VSS and the second ground voltage VSSQ are transferred also mutually share power noises in a low frequency range. In addition, when metal lines occupying a large area are used to short the voltage lines, the layout area of the semiconductor integrated circuit may increase.
Meanwhile, the voltage lines through which the second power supply voltage VDDQ and the first ground voltage VSS are transferred, and the voltage lines through which the first power supply voltage VDD and the second ground voltage VSSQ are transferred, may be shorted using capacitors. When the capacitors shorting the voltage lines are implemented with MOS transistors, the occupied area thereof may become small and the capacitors may operate in only the high frequency range, whereby power noises shared by the voltage lines may decrease. However, current cannot be supplied through the capacitors shorting the voltage lines in the high frequency range, because a closed circuit allowing a current to flow is not formed between the voltage lines through which the second power supply voltage VDDQ and the first ground voltage VSS are transferred, or between the voltage lines through which the first power supply voltage VDD and the second ground voltage VSSQ are transferred.